Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.

BACKGROUND: Exercise intolerance is an independent predictor of poor prognosis in diabetes. The underlying mechanism of the association between hyperglycemia and exercise intolerance remains undefined. We recently demonstrated that the interaction between ARRDC4 (arrestin domain-containing protein 4) and GLUT1 (glucose transporter 1) regulates cardiac metabolism. METHODS: To determine whether this mechanism broadly impacts diabetic complications, we investigated the role of ARRDC4 in the pathogenesis of diabetic cardiac/skeletal myopathy using cellular and animal models. RESULTS: High glucose promoted translocation of MondoA into the nucleus, which upregulated Arrdc4 transcriptional expression, increased lysosomal GLUT1 trafficking, and blocked glucose transport in cardiomyocytes, forming a feedback mechanism. This role of ARRDC4 was confirmed in human muscular cells from type 2 diabetic patients. Prolonged hyperglycemia upregulated myocardial Arrdc4 expression in multiple types of mouse models of diabetes. We analyzed hyperglycemia-induced cardiac and skeletal muscle abnormalities in insulin-deficient mice. Hyperglycemia increased advanced glycation end-products and elicited oxidative and endoplasmic reticulum stress leading to apoptosis in the heart and peripheral muscle. Deletion of Arrdc4 augmented tissue glucose transport and mitochondrial respiration, protecting the heart and muscle from tissue damage. Stress hemodynamic analysis and treadmill exhaustion test uncovered that Arrdc4-knockout mice had greater cardiac inotropic/chronotropic reserve with higher exercise endurance than wild-type animals under diabetes. While multiple organs were involved in the mechanism, cardiac-specific overexpression using an adenoassociated virus suggests that high levels of myocardial ARRDC4 have the potential to contribute to exercise intolerance by interfering with cardiac metabolism through its interaction with GLUT1 in diabetes. Importantly, the ARRDC4 mutation mouse line exhibited greater exercise tolerance, showing the potential therapeutic impact on diabetic cardiomyopathy by disrupting the interaction between ARRDC4 and GLUT1. CONCLUSIONS: ARRDC4 regulates hyperglycemia-induced toxicities toward cardiac and skeletal muscle, revealing a new molecular framework that connects hyperglycemia to cardiac/skeletal myopathy to exercise intolerance.

Potential contribution of erythrocyte microRNA to secondary erythrocytosis and thrombocytopenia in congenital heart disease.

BackgroundChildren with cyanotic heart disease develop secondary erythrocytosis and thrombocytopenia via unknown mechanisms. Mature erythrocyte microRNAs may reflect clinical pathologies and cell differentiation processes pre-enucleation. This study evaluated erythrocyte microRNAs in children with cyanotic heart disease.MethodsErythrocyte microRNAs from children with cyanotic and acyanotic heart disease and without cardiac disease were quantified with Ion PGM System (n=10 per group). Differential expression was confirmed by quantitative PCR (qPCR; n=20 per group).ResultsMir-486-3p, mir-486-5p, and mir-155-5p increased in patients with cyanotic heart disease compared with those without heart disease: fold differences (95% confidence interval): mir-486-3p: 1.92 (1.14-3.23), P=0.011; mir-486-5p: 2.27 (1.41-3.65), P<0.001; and mir-155-5p: 1.44 (1.03-2.03), P=0.028. Mir-486-5p was increased, and let-7e-5p and mir-1260a were decreased in patients with acyanotic heart disease compared with those without heart disease: mir-486-5p: 1.66 (1.03-2.66), P=0.035; let-7e-5p: 0.66 (0.44-0.99), P=0.049; and mir-1260a: 0.53 (0.29-0.99), P=0.045.ConclusionSeveral microRNA levels changed in children with cyanotic and acyanotic heart disease. Mir-486-3p and -5p are associated with hematopoietic differentiation. Mir-486-3p regulates the erythroid vs. megakaryocyte lineage fate decision. Mir-155 is a hypoxia-inducible microRNA, whose overexpression inhibits megakaryocyte differentiation. Erythrocyte microRNA expression changes may contribute to erythrocytosis and thrombocytopenia in children with cyanotic heart disease.

[Interstitial Pneumonia and Emphysema].

Interstitial pneumonia (IP) and chronic obstructive pulmonary disease (COPD) are representative diseases of restrictive pulmonary dysfunction and obstructive pulmonary dysfunction, respectively. In the preoperative anesthesia clinic, anesthesiologists are frequently asked to assess the anesthesia management of patients with these diseases. In respiratory function tests, IP is detected as a decrease in % vital capacity (< 80%), and COPD as a decrease in % FEV1.0 (< 70%). Other key factors which affect the assessment are; 1) severity assessment that affects the safety of anesthesia management, 2) prognostic evaluation including the acute exacerbation in the postoperative period, and 3) patient-related factors (age, life degree of autonomy, other comorbidities, surgery-related factors, and anesthesia method). In the patients in the disease stage I or II, anesthesia management is relatively safe. On the other hand, the patients in the disease stage IV have no surgical indication except life-saving emergent situation. In another words, anesthesiologists are required to make the judgment for the anesthesia management of the patient in the disease stage III, based on the assessment of patient-related factors, surgery-related factors, and prognosis.

Ultrasound-guided radial artery catheterization in infants and small children.

OBJECTIVE: To determine whether ultrasound guidance increases the success rates, decreases the complication rates, and shortens the time to successful radial artery catheterization in infants and small children. DESIGN: Randomized study. SETTING: Single university-affiliated hospital. PATIENTS: Infants and children weighing 3-20 kg, undergoing cardiac surgery for congenital heart disease. INTERVENTION: We randomly assigned the right and left radial arteries of patients undergoing arterial catheterization to ultrasound-guided technique versus the usual palpation technique. MEASUREMENTS: The primary study endpoints were the rates of successful cannulation at first and within three attempts. The secondary endpoints were time to radial artery identification, number of attempts for successful cannulation, and rate of complications. MAIN RESULTS: Compared with palpation, ultrasound-guided radial artery catheterization was successful in 76.3% versus 35.6% of first attempts and in 94.9% versus 50.8% of arteries after three attempts (both comparisons, p < 0.01). The median time [interquartile range] to identification of the arteries (18.5 seconds [11.25-27.25] vs 30 seconds [17.75-39.5]) was significantly shorter (p < 0.01), the number of attempts [interquartile range] at successful cannulation (1 [1-1] vs 2 [1-2]) was significantly fewer (p < 0.01), and the proportion of hematomas (5.1% vs 25.4%) was significantly lower (p < 0.01) in the ultrasound group than those in the palpation group. CONCLUSIONS: In infants and small children, ultrasound-guided radial artery catheterization was more successful and expeditious than the usual palpation technique.

Prediction of pediatric endotracheal tube size by ultrasonography.

BACKGROUND: Formulas based on age and height often fail to reliably predict the proper endotracheal tube (ETT) size in pediatric patients. We, thus, tested the hypothesis that subglottic diameter, as determined by ultrasonography, better predicts optimal ETT size than existing methods. METHODS: A total of 192 patients, aged 1 month to 6 yr, who were scheduled for surgery and undergoing general anesthesia were enrolled and divided into development and validation phases. In the development group, the optimal ETT size was selected according to standard age-based formulas for cuffed and uncuffed tubes. Tubes were replaced as necessary until a good clinical fit was obtained. Via ultrasonography, the subglottic upper airway diameter was determined before tracheal intubation. We constructed a regression equation between the subglottic upper airway diameter and the outer diameter of the ETT finally selected. In the validation group, ETT size was selected after ultrasonography using this regression equation. The primary outcome was the fraction of initial cuffed and uncuffed tube sizes, as selected through the regression formula, that proved clinically optimal. RESULTS: Subglottic upper airway diameter was highly correlated with outer ETT diameter deemed optimal on clinical grounds. The rate of agreement between the predicted ETT size based on ultrasonic measurement and the final ETT size selected clinically was 98% for cuffed ETTs and 96% for uncuffed ETTs. CONCLUSIONS: Measuring subglottic airway diameter with ultrasonography facilitates the selection of appropriately sized ETTs in pediatric patients. This selection method better predicted optimal outer ETT diameter than standard age- and height-based formulas.